Generally, the intensity distribution of a laser beam is spatially Gaussian. In other words, the intensity of a laser beam decrease progressively from the optical axis outward. Accordingly, the intensity is spatially non-uniform.
In order to uniformize the beam intensity, an optical device, referred to as the beam shaper, has been reported to modify the intensity distribution of a light beam. The beam shaper is capable of shaping the beam to uniformize the intensity distribution. The currently available beam shapers are mostly made using refraction and diffraction for beam shaping.